1. Technical Field
The present invention relates to wire bending mechanisms and, more particularly, to a unidirectional wire bending apparatus which includes an air bladder wire securement mechanism which secures a wire to be bent in a bending position, a computer-controlled movably mounted bending unit having a bending head travelling adjacent the wire for bending thereof, and a wire rotation mechanism for rotating the wire so that as the bending unit travels along the wire, the wire may be rotated to permit the formation of three-dimensional bends in the wire.
2. Description of the Prior Art
Various types of wire bending devices are found in the prior art, and as the field of uses for bent wires has expanded, the methods by which the various wire bending devices perform their bending processes have become ever more sophisticated and specialized. Wires are commonly used in many different applications, such as car seats and the like, and for each different seat type, a different bent wire is required to fit within the seat. Therefore, the various wire bending units in the prior art need to accommodate different bend patterns.
Some of the prior art devices include Nihashi U.S. Pat. No. 4,471,819 which discloses an apparatus for making a formed wire which bends wire by holding it at its mid-point by a holder and then consecutively bending the wire by a pair of movable bending units which start at opposite ends of the wire and move towards the center. As the bending units move along the wire, the wire is bent to a desired angle. After a bend is performed, the wire is released by the center clamp and held by clamps on each bending unit. The wire is then rotated to its new position, the center clamp reengages, and the bending units move to the next bending location. Nihashi includes several inherent disadvantages, however, such as the need for additional clamps and for the separate rotational devices which slow the bending process. Furthermore, Nihashi is a large machine, which will take up valuable shop floor space. There is therefore a need for a wire bending device that remedies these deficiencies.
Other prior art devices disclose wire bending devices that are generally inefficient, requiring either manual insertion of wires to be bent or bending devices which only permit two-dimensional bending. There is therefore a need for a wire bending device which is capable of feeding wires automatically into the bending section of the device and which includes a wire rotating device to permit the formation of three-dimensional bends in the wire.
One common type of wire bending device includes a wire feed which moves the wire past the bending head during the bending process. A major problem encountered in the operation of these devices is that the error tolerances for wire bends are often smaller than the error margins of the machine, which means that several pieces out of each production run will be unsuitable for their intended use. The errors arise due to the motion of the wire in different axes from the axis of movement of the wire, i.e., flexing of the wire during movement. To prevent this movement, many of the prior art devices xe2x80x9cthreadxe2x80x9d the wire through a guide hole adjacent the bend head. Of course, while the bend head guide hole will substantially eliminate the flexing of the wire, it also adds a removal step to the bending process, which decreases the rate at which wires will be produced and renders the device less efficient. There is therefore a need for a wire bending device that holds the wire in a stationary position during the bending process while the bending head travels along the wire.
Another problem encountered in the prior art is that the majority of bending devices support the wire above the bending unit, which forces the operator of the device to remove the wire from the machine after bending instead of the wire being released to fall into a stocking bin or the like. Again, the inefficiencies inherent in this design are obvious and there is a need for a solution to this design flaw.
Therefore, an object of the present invention is to provide an improved wire bending device.
Another object of the present invention is to provide a wire bending device which will automatically feed wires to be bent into the bending section of the device.
Another object of the present invention is to provide a wire bending device which includes a bending head and a wire securement device that rotates the wire to permit three-dimensional bending of the wire.
Another object of the present invention is to provide a wire bending device that is at least partially computer-controlled to enable rapid resetting of bend positions in the wire and to allow for multiple bend patterns to be accessed and used without requiring resetting of the bend information.
Another object of the present invention is to provide a wire bending device which includes a wire securement device such as an air bladder actuated chuck that will hold a very short section of the end of the wire to permit substantially the entire wire to be bent.
Finally, an object of the present invention is to provide a wire bending device which is relatively simple and sturdy in construction and is safe and efficient in use.
The present invention provides a wire bending device which includes an upright frame and a wire feed hopper for dispensing wire rods, the hopper mounted on the frame. A wire bending section is mounted on the frame, and at least one transport arm is pivotally mounted on the frame, the transport arm including a releasable wire holding device such as a magnet mounted thereon for releasably holding a wire rod, the transport arm being operative to transport wire rods from the hopper to the wire bending section of the device. The wire bending section includes a rotatable wire securement device mounted on the frame and having a center longitudinal axis, the rotatable wire securement device operative to secure one end of a wire rod and rotate the wire rod about its longitudinal central axis and a wire bending unit movably mounted on the frame, the wire bending unit including a wire bend head aligned with the center longitudinal axis of the rotatable wire securement device, the wire bending unit adapted to move on the frame such that the wire bend head remains aligned with the center longitudinal axis of the rotatable wire securement device. A control unit such as a programmable computer is operatively connected to the transport arm, the rotatable wire securement device and the wire bending unit, the control unit programmed to engage the transport arm to transport a wire rod from the hopper to the wire bending section, engage the rotatable wire securement device to secure one end of the wire rod, move the wire bend head to determined bend locations on the wire rod and rotate the wire rod about its longitudinal central axis to programmed positions, and engage the wire bend head to perform the programmed bend in the wire rod.
The present invention thus provides a substantial improvement over those bending devices found in the prior art. For example, many devices require manual insertion of wires to be bent into the device, whereas the present invention automatically feeds wires into the bending section. Furthermore, because the present invention provides for rotation of the wire rod, three-dimensional bends may be formed in the wire. Also, the precise controllable positioning of the wire bend head greatly reduces the chances of unusable wires being produced. Repeatability and consistency are the hallmarks of the present invention, and thus it is seen that the present invention is superior to those devices found in the prior art.